Polling began in four naxalite-hit constituencies in Bihar's Gaya district on Friday morning amid tight security, with Indian Air Force helicopters maintaining aerial surveilance, official sources said.

Polling in these places, earlier scheduled for October 18, was postponed to Friday by the Election Commission to facilitate effective deployment of security forces. All the 1005 booths are being manned by Border Security Force, Indo-Tibetan Border Police and Central Reserve Police Force personnel.

Four IAF choppers were patrolling the skies in the four hyper-sensitive constituencies, where naxalites have given a call for boycott of elections.

There are 43 candidates in the fray, including nine each in Belaganj, Gaya (town) and Bodh Gaya, besides 16 in Gaya(mofussil).